Minimally open retraction device

ABSTRACT

A retractor having a pair of blades is disclosed. A ring having an opening is attached to one end of the blades. The blades define a channel therebetween. The blades may be pivotally coupled to the ring. The retractor may have at least two conditions. In a first condition, the retractor is insertable through an incision in a patient&#39;s skin to an operative site. In a second condition, the retractor may be manipulated for retracting tissue surrounding the operative site. Instruments, prostheses, or tissue may be inserted or removed through the channel of the retractor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.14/833,609, filed Aug. 24, 2015, which is a division of U.S. patentapplication Ser. No. 14/228,639, filed on Mar. 28, 2014, now U.S. Pat.No. 9,131,934, which is a division of U.S. patent application Ser. No.11/799,576, filed on May. 2, 2007, now U.S. Pat. No. 8,696,560, whichclaims priority to, and the benefits of, U.S. Provisional PatentApplication Ser. No. 60/796,921 filed on May. 2, 2006, the entirecontents of each of these prior applications are incorporated herein byreference.

BACKGROUND

1. Technical Field

The present disclosure relates generally to orthopedic spine surgeryand, in particular, to a minimally open retraction device and methodsfor its use in a minimally open surgical procedure.

2. Background of Related Art

In recent years minimally open surgical approaches have been applied toorthopedic spine surgery and more recently to spine fusions involvingone or more vertebral bodies. Unlike minimally invasive procedures suchas arthroscopic knee surgery or gallbladder surgery where the affectedarea is contained within a small region of the body, spine surgeryinvolving a fusion typically spans a considerably larger length orportion of the body. For this reason, the idea of performing a minimallyopen procedure on the spine has only recently been approached.

Minimally open surgery offers significant advantages over conventionalopen surgery. At the onset, the skin incision and subsequent scar aresignificantly smaller. By using more than one small incision rather thanone large incision the need for extensive tissue and muscle retractionis greatly reduced. This leads to significantly less post-operativepain, shorter hospital length-of-stay and a faster recovery overall.

A truly minimally open spine procedure should constitute the smallestdamage or disruption possible to the surrounding anatomy. While theremay be more than one incision or one long incision, depending on thenumber of levels needing attention, it is the amount of muscleretraction and scraping that will result in less operative trauma forthe patient. A minimally open procedure is also less expensive, reduceshospitalization time, causes less pain and scarring, reduces theincidence of complications, such as surgical site infections, and has anincreased speed of recovery.

A typical spine fusion in the lumbar region, whereby at least twovertebral bodies are rigidly connected using screws implanted into thevertebral body and a solid metal rod spanning the distance between saidscrews, is by its nature not very conducive to a minimally openapproach. Furthermore, a spine fusion is typically supported byimplanting one or more interbodies into the disc space either using ananterior or posterior approach. An anterior approach requires a separateincision whereby the surgeon accesses the patient's spine through theabdomen. One advantage is the interbody used in this procedure closelymatches the footprint of the adjacent vertebral bodies. The disadvantageis that an anterior procedure is typically performed at a different timeand requires its own incision and access.

A posterior approach to interbody implantation can be achieved throughthe same incision as that of the pedicle screws. Implantation of aPosterior Lumbar Interbody Fusion (PLIF) device requires bilateralremoval of the facet joint while implantation of a Transforaminal LumbarInterbody Fusion (TLIF) device can be achieved unilaterally and mayrequire removal of only one facet joint. The advantage of the TLIF isthat only one device is implanted into the disc space whereas a PLIFrequires two bilateral implants.

While the implantation of pedicle screws can be achieved with relativelylittle site preparation, interbody implantation requires considerablework. Once the facet joint is removed, the surgeon can begin removingthe disc. One or more instruments may be needed to access the site atany time as well as sufficient lighting and suction. To perform thesetasks the surgeon needs a suitable opening or channel to work through.

There has been considerable development of retractors and retractorsystems for minimally invasive procedures, with most of the newtechnologies being based on traditional types of surgical retractors foropen procedures, predominantly table-mounted devices of various designs.These prior art devices are large and bulky and frequently do not adaptwell to a less invasive approach. Standard hand-held surgical retractorsare well known in the prior art and can be modified to fit the contoursof these smaller incisions, but they require manual manipulation tomaintain their position. Typical retractors also are positioned into thesoft tissue and levered back to hold the wound open, frequentlyrequiring re-positioning if they dislodge, obstruct the view, or theaccess ways.

Several minimally open or minimally invasive access devices currentlyexist to achieve the goal of a suitable working channel. Most are eithermounted to the surgical table or held in place by the surgeon or anassistant. Table mounted retractors offer little by way of flexibility.Furthermore, they do not offer a relationship or positional guidancewith respect to the patient.

Handheld retractors offer greater flexibility but require an extra handto maintain position. They also may or may not offer a fixedrelationship to the patient but in either case can easily be knocked outof position. Furthermore, handheld retractors typically offer a verylong and narrow fixed channel to work through making the procedure evenmore challenging. Finally, any of the above mentioned retractorstypically require a form of dilation to obtain the initial opening.Circular or oblong dilators are well known in the art.

SUMMARY

The present disclosure is directed towards retractors configured for usein minimally invasive procedures. In particular, embodiments of thepresent disclosure include retractors that are configurable forinsertion through a minimal opening in the patient's skin and arereconfigurable for retracting tissue surrounding a selected operativesite.

According to one embodiment of the present disclosure, the minimallyopen retraction device includes first and second elongate members orblades. The blades are generally arcuate and define a generally funnelshaped channel that extends through the retractor. A ring member isattached to the distal ends of the blades. The ring member has anopening extending therethrough. The blades are repositionable between aclosely approximated position and a spaced apart position. In theclosely approximated position, the retractor is insertable and removablethrough the incision in the patient's skin. After the retractor isinserted into an operative site, the blades are manipulated by thepractitioner to retract tissue surrounding the operative site. Inaddition, the ring member may include opposing rod portions forattaching the retractor to pedicle screws located in the operative site.

According to another presently disclosed embodiment, the retractorincludes first and second sections. Each section includes a ring portionattached to a distal end of an elongate member or blade. The blade has agenerally arcuate configuration. A pair of rod portions extends outwardsfrom opposing ends of the ring portion. The rod portions of one sectioninclude complementary structures for slidably engaging the correspondingrod portions of the other section such that the rod portions areslidable relative to each other. When assembled, the ring portionsdefine an opening and the arcuate blades define a generally funnelshaped channel that is in communication with the opening. Since the rodportions are slidably coupled, the size and shape of the opening isvariable. As in the previous embodiment, the retractor may be coupled topedicle screws.

In a further embodiment of the minimally open retraction device orretractor, the retractor includes a pair of elongate members or bladesthat are operatively coupled to a ring member. The ring member islocated at the distal ends of the blades and has an openingtherethrough. Each blade includes a hole near its distal end. The holecooperates with a loop that is attached to the ring member such thateach blade is pivotally coupled to the ring member. A pair of opposingrod portions is attached to the ring member. As such, the retractorblades can be repositioned into close approximation with each other thatrotates the ring about an axis of the rod portions. In this state, theretractor has a minimal profile and may be inserted through a minimalincision or opening in the patient. Once inserted, the retractor ismanipulated to a second state for retracting tissue surrounding theoperative site. As in previous embodiments, the retractor may beattached to pedicle screws located in the operative site.

In an alternative embodiment of the present disclosure, the minimallyopen retraction device or retractor includes an arcuate member havingopposing rod portions extending from the ends of the arcuate member. Oneblade includes a hole that cooperates with a loop attached to thearcuate member. The other blade has an arcuately shaped cutout in itsdistal region and a pair of protrusions with bores. The bores are sizedto cooperate with the rod portions such that the blade is rotatableabout the rod portions. In addition, the arcuate cutout and the arcuatemember define an opening in the retractor.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the presently disclosed minimally open retraction deviceare described herein with reference to the accompanying drawings,wherein:

FIG. 1A is a top view of a minimally open retraction device according toan embodiment of the present disclosure;

FIG. 1B is a front perspective view of the minimally open retractiondevice of FIG. 1A;

FIG. 1C is a front perspective view of the minimally open retractiondevice of FIG. 1A attached to a pair of pedicle screws;

FIG. 2A is a top view of a first section of a minimally open retractiondevice according to another embodiment of the present disclosure;

FIG. 2B is an enlarged bottom perspective view of a second section ofthe minimally open retraction device illustrating features of extensionmembers;

FIG. 2C is a bottom perspective view of the two sections of theminimally open retraction device of FIGS. 2A and 2B as assembled;

FIG. 3A is a side perspective view of a minimally open retraction deviceaccording to a further embodiment of the present disclosure in a firststate;

FIG. 3B is a front view of the minimally open retraction device of FIG.3A;

FIG. 3C is a top view of the minimally open retraction device of FIG. 3Ashown in a second state;

FIG. 3D is a front perspective view of the minimally open retractiondevice of FIG. 3C;

FIG. 3E is a side perspective view of the minimally open retractiondevice of FIG. 3A attached to a pair of pedicle screws;

FIG. 4A is a side perspective view of a minimally open retraction devicein a first state according to an alternate embodiment of presentdisclosure;

FIG. 4B is a side perspective view of the minimally open retractiondevice of FIG. 4A in a second state;

FIG. 4C is a top view of the minimally open retraction device of FIG.4A;

FIG. 4D is a side perspective view of the minimally open retractiondevice of FIG. 4B attached to a pair of pedicle screws;

FIG. 4E is a top perspective view of an alternate embodiment of theminimally open retraction device of FIG. 4A;

FIG. 5A is a perspective view of a further embodiment of the presentlydisclosed minimally open retraction device;

FIG. 5B is a bottom perspective view of the minimally open retractiondevice of FIG. 5A shown in one configuration;

FIG. 5C is a bottom perspective view of the minimally open retractiondevice of FIG. 5A shown in a second configuration;

FIG. 6A is a top plan view of a minimally open retraction deviceaccording to a further embodiment of the present disclosure;

FIG. 6B is a side plan view of the minimally open retraction device ofFIG. 6A;

FIG. 7A is a top perspective view of a minimally open retraction deviceaccording to an alternate embodiment of the present disclosure;

FIG. 7B is a bottom perspective view of the minimally open retractiondevice of FIG. 7A in an insertion condition;

FIG. 8 is a side perspective view of a temporary set screw; and

FIG. 9 is a top perspective view of the minimally open retraction deviceof FIG. 4E installed onto a pair of pedicle screws.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments of the presently disclosed minimally open retraction devicewill now be described in detail with reference to the drawing figureswherein like reference numerals identify similar or identical elements.In the drawings and in the description which follows, the term“proximal”, as is traditional, will refer to the end of the minimallyopen retraction device which is closest to the operator while the term“distal” will refer to the end of the device which is furthest from theoperator.

Referring now in detail to FIGS. 1A-1C, in which like reference numeralsidentify similar or identical elements, a minimally open retractiondevice, in accordance with a first embodiment of the disclosure, isgenerally designated as 100.

As shown in FIGS. 1A and 1B, a minimally open retraction device, orretractor 100 includes first and second elongate members or blades 110,120. Each of the blades 110, 120 include a proximal end 112, 122 and adistal end 114, 124. In addition, each blade 110, 120 is arcuatelyshaped and formed from a resilient polymeric material. The distal ends114, 124 are attached to a ring 130 that includes an opening 132therethrough. On opposing portions of the ring 130 are rod portions orextension members 140, 150. The ring 130 and the rod portions 140, 150are formed from polyethylene. Although the rod portions 140, 150 areillustrated as having a cross shaped configuration, other geometricshapes are contemplated (e.g. circular, hexagonal, or rectangular). Itis contemplated that the distal ends 114, 124 of the blades 110, 120 areintegrally formed with the ring 130.

It is further contemplated that other suitable biocompatible materials(e.g. polyethylene, polypropylene, polycarbonate, polyetheretherketone,stainless steel, or titanium) may be used. In instances where a metallicmaterial is selected, the material has a thickness that allows eachblade 110, 120 to bend and retract tissue. It is also contemplated thatthe thickness of each blade 110, 120 may vary along its length, therebyadjusting its rigidity and flexibility for a selected procedure.

The ring member 130 is formed from a material that is more rigid thanthe material selected to form blades 110, 120. By forming the ringmember 130 from a more rigid material than the blades 110, 120, thegeometry of the retractor 100 and the opening 132 are maintained duringretraction of the surrounding tissue. In addition, each of the blades110, 120 include a plurality of orifices 50. The orifices 50 are adaptedto cooperate with a conventional instrument such as a Gelpi retractor.

Each blade 110, 120 is generally arcuate such that when the blades 110,120 are moved towards each other (i.e. approximated), the retractor 100defines a funnel shaped channel 160 therebetween. The channel 160 is incommunication with the opening 132 of the ring 130. As such, the channel160 permits access to the operative site and the introduction and/orremoval of surgical instruments, tissue, or prosthetic devices from theoperative site.

In addition, as shown in FIG. 1C, the retractor 100 may be coupled to apair of pedicle screws 10. As is known in the art, the pedicle screwsmay be monoaxial or polyaxial. Each pedicle screw 10 includes a head 12defining a channel 14. A set screw 16 may be threaded into the head 12.The pedicle screw 10 also includes a threaded shank 18 for engagementwith a selected bone structure (e.g. a vertebral body). Each of the rodportions 140, 150 is configured and adapted to fit within the channel 14of the pedicle screw 10. When a rod portion 140, 150 is positionedwithin the channel 14, the set screw 16 is tightened and secures the rodportion 140, 150 relative to the pedicle screw 10. The set screw 16 maybe loosened so that the practitioner may adjust the positioning of therod portion 140, 150 relative to the pedicle screw 10 and thenre-tightened when the rod portion 140, 150 is in a desired position. Inaddition, the structural rigidity of the ring member 130 maintains thedistance between the pedicle screws 10 during the surgical procedure.

The retractor 100 is installed through an incision or opening created inthe patient's skin using techniques and instruments that are known inthe art. In one embodiment, the retractor 100 is installed through aminimal incision or opening. Once the incision is made in a desiredlocation and the pedicle screws 10 are positioned in the selected bonestructures, the retractor 100 is inserted into the incision. Workingsubcutaneously, the practitioner manipulates the retractor 100 into adesired position and maneuvers the rod portions 140, 150 into thechannels 14 of the respective pedicle screws 10. The retractor 100 maythen be moved along an axis defined between the pedicle screws 10,thereby allowing the practitioner to finely adjust the location of theretractor 100. Once the retractor 100 is in the desired location, thepractitioner tightens the set screws 16 to secure the position of theretractor 100. Additionally, one or both of the set screws 16 may beloosened or loosely installed in their respective pedicle screws 10,thereby allowing the practitioner to reposition the retractor withoutnecessitating removal and reinstallation of the retractor 100.Subsequent to any repositioning, the practitioner tightens the setscrews 16 to lock the retractor 100 in position.

Once the retractor 100 is in the desired location, the practitionermanipulates the blades 110, 120 by bending them outwards to retracttissue at the operative site, thereby increasing the size of the accessopening at the operative site. As such, the retractor 100 may beinserted through a relatively small opening and expanded to enlarge theopening for subsequent surgical procedures. Instruments, tissue, and/orprosthetic devices may then be inserted or removed through the opening132. The channel 160 and the opening 132 provide a convenient accessportal for the practitioner to perform surgical procedures at theoperative site.

Advantageously, the shape of the access opening created using thedevices and methods disclosed herein is generally funnel shaped, with anarrower section disposed within the incision localized on the area ofinterest between the pedicle screws, the location of the ring at thebase of the funnel being secured relative to the pedicle screws. Thefunnel shape defined by the retractor with the flexible blades spreadapart provides increased access space at the proximal portion of theincision, thereby providing increased visibility and the ability toinsert and remove additional instrumentation such as suction, irrigationor lighting without interfering with the surgeon's ability to operate inthe operative area at or below the bottom of the funnel shaped device.

In an alternate embodiment of the present disclosure, a minimally openretraction device is illustrated in FIGS. 2A-2C. The minimally openretraction device, or retractor is generally designated as 200 (FIG.2C). FIG. 2A illustrates one section 200 a of the retractor 200 with theother section 200 b being substantially similar. The section 200 aincludes an elongate member or blade 210 having a proximal end 212 and adistal end 214. The blade 210 is arcuately shaped and formed from aflexible polymeric material similar to the materials used inmanufacturing retractor 100. An arcuate ring 230 is attached to thedistal end of the retractor 200. The arcuate ring 230 is formed fromring portions 230 a, 230 b that are at the distal ends 214, 224 of theblades 210, 220 (FIG. 2C). It is contemplated that the distal ends 214,224 are integrally formed with the ring portions 230 a, 230 b. At theends of the ring member 230, a pair of opposing rod portions 240, 250 isattached. The ring member 230 and the rod portions 240, 250 combine todefine a substantially hemispherical structure. In particular, the rodportions 240, 250 are attached to opposing ends of the ring member 230and extend outwards therefrom. The ring member 230 is formed from aresilient polymeric material and may be stretched or compressedaccordingly.

The rod portions 240, 250 are generally hemispherical structures. Eachof the rod portions 240, 250 include a planar surface 244, 254. As shownin FIGS. 2B and 2C, the planar surface 244 of rod portion 240 isseparated from the planar surface 254 of rod portion 250 byapproximately 180°. Further still, the planar surface 244 includes a rib242 that extends above the surface of planar surface 244. The planarsurface 254 includes a channel 252 that is recessed below the planarsurface 254. The rib 242 and the channel 252 are complementary in thatthey are both configured and dimensioned for slidably engaging oneanother.

As assembled, the retractor 200 (FIG. 2C) includes first and secondsections 200 a, 200 b. The sections 200 a, 200 b are coupled togethersuch that the ribs 242 slidably engage the channels 252 as describedhereinabove. This arrangement permits the practitioner to vary the sizeof the opening 232 as will be described in detail hereinbelow. As in theprevious embodiment, the blades 210, 220 are bendable in relation to thering 230 such that the retractor 200 retracts tissue surrounding theoperative site.

Similar to the previous embodiment, the operative site is prepared byforming an incision or an opening in the patient's skin using knowntechniques and equipment. The pedicle screws 10 may be installed in theselected bone structures either before the incision is made orsubsequent to its creation. Once the incision is created at theoperative site, the practitioner installs the retractor 200.

In a first technique, the practitioner couples the first and secondsections 200 a, 200 b as described above and inserts the assembledretractor 200 into the incision. The assembled retractor 200 may bepositioned between the pedicle screws 10 using the techniques discussedwith regards to retractor 100. As such, the retractor 200 may besubstituted for the retractor 100 that is illustrated in FIG. 1C. Theslidable arrangement between the first and second sections 200 a, 200 bpermits the practitioner to vary the size and configuration of theopening 232. After the assembled rod portions 240, 250 are positioned intheir respective channels 14 of the pedicle screws 10, the practitionermay slide the respective rod portions 240, 250 relative to one another,thereby expanding or contracting (i.e. re-configuring) the opening 232.Thus, the retractor 200 is capable of being installed through anincision and joining adjacent pedicle screws 10 without the necessity ofsizing the retractor 200 to the operative site prior to commencing thesurgical procedure. As such, the increased flexibility of the retractor200 allows the practitioner to install the pedicle screws 10 in desiredlocations, form the incision between the pedicle screws 10, install theretractor 200, and adjust the size of the opening 232 for accommodatingthe distance between the pedicle screws 10.

As shown in FIG. 2C, the retractor 200 is in its default condition. Inthis condition, the effective length of the retractor 200 is defined bythe distance between the distal ends of the rod portions 240, 250 ofeither section 200 a, 200 b. If the distance between the pedicle screws10 is greater than the distance between the end regions of the rodportions 240, 250, the practitioner merely slides the rod portions 240,250 away from each other (i.e. away from a center of the opening 232)and effectively increases the overall length of the retractor 200 suchthat it may be attached to the pedicle screws 10 and locked in positionusing the set screws 16. Alternatively, if the distance between thepedicle screws 10 is less than the distance between the rod portions240, 250, the practitioner may slide the rod portions 240, 250 towardseach other (i.e. towards a center of the opening 232) and effectivelyreduce the overall length of the retractor 200 prior to securing it tothe pedicle screws 10 using the set screws 16. In addition, by alteringthe effective length of the retractor 200, the configuration of theopening 232 in ring 230 is also altered. When the effective length ofthe retractor 200 is increased, the ring portions 230 a, 230 b arestretched and define a generally elliptical opening having its long axisalong a longitudinal axis of the rod portions 240, 250. When theeffective length of the retractor 200 is decreased, the ring portions230 a, 230 b are compressed forming a generally elliptical opening withits short axis along the longitudinal axis of the rod portions 240, 250.

Referring now to FIGS. 3A-3E, a further embodiment of the presentdisclosure is illustrated. The minimally open retraction device orretractor is generally designated as 300. The retractor 300 includesfirst and second elongate members or blades 310, 320. Each blade 310,320 includes a proximal end 312, 322 and a distal end 314, 324. Inaddition, each blade 310, 320 has a generally arcuate shape. The ringmember 330 is attached to the distal ends 314, 324 of the blades 310,320. The ring member 330 is a circular structure having an opening 332and a pair of outwardly extending rod portions 340, 350. As in each ofthe previous embodiments, the ring member is formed from a materialhaving greater rigidity (i.e. structural strength) that the materialused to form each of the blades 310, 320. By using a more rigidmaterial, the ring member 330 maintains its geometry during the surgicalprocedure and further maintains the distance between the pedicle screws10 as will be discussed hereinbelow in connection with FIG. 3E.

Each of the rod portions 340, 350 have a generally cylindrical shape andare located in opposition to one another such that they areapproximately 180° apart from each other on an outer surface of the ringmember 330. The rod portions 340, 350 may also have different geometricconfigurations such as rectangular, hexagonal, or cross shaped. Theblades 310, 320 are pivotally coupled to the ring member 330 and arepositioned such that the points of attachment are approximately 180°apart on the ring member 330. In one embodiment, the distal ends 314,324 are pivotally coupled to the ring member 330 via loops 316, 326. Theloops 316, 326 are fixedly attached to the ring member 330, while eachof the blades 310, 320 are movable along the loops 316, 326 via a hole318, 328 (FIG. 3E) in each of the blades 310, 320. Thus, the blades 310,320 are capable of retracting surrounding tissue once the retractor 300is positioned in a desired location by urging the blades 310, 320 awayfrom each other and retracting the surrounding tissue. As in theprevious embodiments, one or both of the blades 310, 320 may bemanipulated to retract tissue.

The retractor 300 is capable of being transitioned from a firstcondition (FIG. 3A) to a second condition (FIG. 3C). In the firstcondition, the retractor 300 has a minimum profile, thereby facilitatingits insertion into an operative site since the blades 310, 320 are inclose approximation with each other and the ring member 330 issubstantially parallel with at least one of the blades. By manipulatingthe blades 310, 320, the practitioner rotates the ring member 330 to aposition that is substantially perpendicular to the blades 310, 320(i.e. the second condition) when the retractor 300 is located in theoperative site, thereby defining the opening at the base of theretractor 300 adjacent the pedicle screws 10.

Specifically referring to FIG. 3E, the retractor 300 is shown connectedto a pair of pedicle screws 10. The pedicle screws 10 are attached toselected bone structures in the patient's body using techniques andinstruments that are known in the art. Once the incision is made in adesired location and the pedicle screws 10 are positioned in theselected bone structures, the retractor 300 is inserted into theincision with the retractor 300 initially in its first condition (i.e. aminimal profile). Working subcutaneously, the practitioner manipulatesthe retractor 300 into a desired position and maneuvers the rod portions340, 350 into the channels 14 of the respective pedicle screws 10. Theretractor 300 may then be moved along an axis defined between thepedicle screws 10 allowing the practitioner to finely adjust thelocation of the retractor 300. Once the retractor 300 is in the desiredlocation, the practitioner tightens the set screws 16 to secure theposition of the retractor 300. Alternatively, one or both of the setscrews 16 may be loosened or loosely installed in their respectivepedicle screws 10, thereby allowing the practitioner to reposition theretractor without necessitating removal and reinstallation of theretractor 300. Subsequent to any repositioning, the practitionertightens the set screws 16 to lock the retractor 300 in position.

Once the retractor 300 is in the desired location, the practitionermanipulates the retractor 300 and spreads apart the retractor blades310, 320, such that the retractor 300 transitions from its firstcondition to its second, funnel-shaped condition, thereby allowing thepractitioner access to the operative site and retracting tissuesurrounding the operative site. In addition, the practitionermanipulates the blades 310, 320 by bending them outwards to retracttissue at the operative site, thereby increasing the size of the openingat the operative site. As such, the retractor 300 may be insertedthrough a relatively small opening and expanded to enlarge the openingfor subsequent surgical procedures. Instruments, tissue, and/orprosthetic devices may then be inserted or removed through the opening332. The channel 360 and the opening 332 provide a convenient accessportal for the practitioner to perform surgical procedures at theoperative site. In addition, since the ring member 330 is formed from amaterial that is more rigid than the material selected for the blades310, 320, the ring member 330 maintains its geometric configurationduring the retraction process. Additionally, since the ring member 330resists deformation, it maintains the relative positions of the pediclescrews 10 to each other during the retraction procedure.

Another embodiment of the presently disclosed minimally open retractiondevice is illustrated in FIGS. 4A-4D and is generally designated as 400.The minimally open retraction device or retractor 400 includes first andsecond elongate members or blades 410, 420. Each blade 410, 420 includesa proximal end 412, 422 and a distal end 414, 424. In addition, eachblade 410, 420 has a generally arcuate shape. The distal end 424 of theblade 420 has an arcuately shaped cutout 423. An arcuate member 430 isreleasably and pivotably coupled to the distal ends 414, 424 of theblades 410, 420. The arcuate member 430 has a pair of outwardlyextending rod portions 440, 450. Each of the rod portions 440, 450 has agenerally cylindrical shape and is located in opposition to one anothersuch that they are approximately 180° apart from each other on an outersurface of the arcuate member 430. In particular, the rod portions 440,450 extend in opposing directions from ends of the arcuate member 430.

In this embodiment, one blade 410 is pivotally coupled to the ringmember 430 via a loop 416. The loop 416 is slidably attached to the ringmember 430 and the blade 410 is movable along the arcuate member 430 bysliding the blade 410 and the loop 416. Thus, the blade 410 is capableof retracting surrounding tissue once the retractor 400 is positioned ina desired location by urging the blade 410 away from the opposing blade420 and retracting the surrounding tissue. In addition, the blade 410may be repositioned relative to the rod portions 440, 450 by sliding theblade 410 and the loop 416 along the arcuate path defined by the ringmember 430. The other blade 420 has first and second protrusions 426,428 depending therefrom. Each of the protrusions 426, 428 has a bore427, 429 extending therethrough. The bores 427, 429 are configured tocooperate with the rod portions 440, 450 such that the protrusions 426,428 are rotatable about the rod portions 440, 450. Accordingly, theblade 420 is rotatable about the rod portions 440, 450. When the blade420 is moved away from the blade 410, the cutout 423 and the arcuatemember 430 define a circular opening 432 through the retractor 400.Additionally, the arcuately shaped blades 410, 420 define a funnelshaped channel 460 when they are spaced apart from one another (FIG. 4C)which is wider at the proximal portion of the incision and narroweradjacent the pedicle screws 10. As in the previous embodiments, one orboth of the blades 410, 420 may be manipulated to retract tissue. Inaddition, the retractor 400 has at least a first condition and a secondcondition. In the first condition, the blades 410, 420 are in closeapproximation with each other and define a minimum profile (i.e. thefirst condition) for the retractor 400. In the first condition, theretractor 400 is adapted and configured for insertion into a relativelysmall opening or incision in the patient's skin. In the secondcondition, the retractor 400 is configured and adapted for retractingtissue surrounding the operative site. Once the retractor 400 ispositioned in a selected location, the practitioner manipulates theblades 410, 420 away from each other and retracts the tissue surroundingthe operative site. As the blade 420 is manipulated, the protrusions426, 428 rotate relative to the rod portions 440, 450 thereby increasingthe size of the opening 432. Retracting tissue using the retractor 400is substantially similar to retracting tissue with previous embodimentsof the retractor. In addition, the retractor 400 can be attached to apair of pedicle screws in the same manner as the retractor 300 asillustrated in FIG. 4D. The arcuate member 430 is formed from a materialthat is more rigid than the material used to form the blades 410, 420and has the attendant advantages discussed with respect to the ringmember 330.

A further embodiment of the retractor is illustrated in FIG. 4E and isgenerally designated as 500. The retractor 500 has substantially thesame or similar components as the retractor 400 with the differencesbeing discussed in detail hereinafter. In this embodiment, blade 520 hasa proximal end 512, an arcuate cut-out 523, and a pair of distal endportions 514 a, 514 b. A loop 516 is attached to each distal end portion514 a, 51 b. The loops are configured and adapted to encircle the rodportions 440, 450 such that the blade 520 is pivotable about the rodportions 440, 450. The arcuate cut-out 523 and the ring member 430define an opening 532. The blades 410, 520 have a generally arcuateconfiguration and define a funnel shaped channel 560 therebetween whenthe instrument is in a second condition. As in the previous embodiments,the retractor 500 can be manipulated between a first condition having aminimal profile for insertion into a minimal incision in the patient'sskin and a second condition for retracting tissue and accessing theoperative site. In the second condition, instruments, prosthetics,and/or tissue may be inserted or removed through the channel 560, whichprovides access to the operative site for the practitioner.Additionally, the blades 410, 520 include a plurality of orifices 50.

Referring now to FIGS. 5A-5C, an alternate embodiment of the presentlydisclosed minimally invasive retraction device or retractor isillustrated and referenced as 600. In this embodiment, the retractor 600is formed as an integrated unit similar to the retractor 100 (FIG. 1A).The retractor 600 includes elongate members or blades 610, 610 and rodportions 640, 650. Each of the blades 610, 620 include a plurality oforifices 50. Additionally, the blades 610, 620 include a proximal end612, 622 and distal end portions 614, 624. The distal end portions 614of the blade 610 are spaced apart from one another and define an arcuatecut-out 613. Similarly, the distal end portions 624 of the blade 620 arespaced apart from one another and define an arcuate cut-out 623. Thearcuate cut-outs 613, 623 define an opening 632 through the retractor600. Furthermore, each of the distal end portions 614, 624 includes anotch 634 that extends partially through the respective distal endportion 614, 624 and defines a flexion joint about which the blades 610,620 may be bent that is best illustrated in FIGS. 5B and 5C. A strut 636connects the distal end portions 614, 624 to the rod portions 640, 650.

The retractor 600 is initially substantially planar (FIG. 5A) and ismanipulated by the practitioner such that the blades 610, 620 are movedtowards each other with the notches 634 defining the point about whichthe blades 610, 620 bend. After the blades 610, 620 are bent (FIG. 5B),the retractor 600 is in a first condition and has a minimal profile,thereby allowing the retractor 600 to be inserted into a minimal openingin the patient's skin. Once the retractor is positioned in a selectedarea of the patient's body, the practitioner can manipulate theretractor 600 to place it in a second condition (FIG. 5C) for retractingtissue surrounding the selected operative site. In the second condition,the blades 610, 620 define a channel 660 therebetween. In particular,the channel 660 is in communication with the opening 632 and permitsaccess to the operative site for the introduction and/or removal ofsurgical instruments, tissue, or prosthetic devices from the operativesite.

The retractor 600 further includes rod portions 640, 650 for releasablycoupling the retractor 600 to a pair of pedicle screws using the sametechniques previously discussed with respect to the retractor 100.

The blades 610, 620 may be formed from suitable materials as previouslydiscussed with regards to the blades 110, 120 of the retractor 100. Thestruts 636 are formed of a more rigid material than are the blades 610,620. Using a more rigid material for the struts 636 provides the samebenefits to the retractor 600 as did the ring member 330 to theretractor 300. Specifically, using a more rigid material for the struts636 provides increased rigidity and stability of the retractor 600 suchthat the retractor 600 maintains its geometry during the retractionprocedure and maintains the retractor 600 in position relative to theinstalled pedicle screws. Consequently, the pedicle screws are alsoinhibited from movement away from their selected installation position.That is, the selected distance between the pedicle screws remainssubstantially constant throughout the surgical procedure.

In a further embodiment of the present disclosure, the minimally openretraction device or retractor is illustrated in FIGS. 6A-6B andreferenced as 700. The retractor 700 includes first and second blades710, 720. The blades 710, 720 include proximal portions 712, 722 anddistal end portions 714, 724. The distal end portions 714 of the blade710 are spaced apart from one another and define an arcuate cut-out 713.Similarly, the distal end portions 724 of the blade 720 are spaced apartfrom one another and define an arcuate cut-out 723. Each blade 710, 720includes a pair of feet 716, 726 attached to the respective distal endportions 714, 724. The feet 716, 726 extend away from the arcuatecut-outs 713, 723 and are substantially orthogonal to a plane defined bythe respective blades 710, 720. Each foot 716, 726 has a hole 702extending therethrough. The holes 702 may be circular, elliptical, oroblong. When the holes 702 of blade 710 are aligned with the holes 702of blade 720, the arcuate cut-outs 713, 723 define an opening 732 thatpermits access to the operative site similar to the opening 632discussed with respect to the retractor 600. In this embodiment, theblades 710, 720 are formed from materials that were previously discussedwith regards to the retractor 100.

Alternatively, as seen in FIGS. 7A and 7B, the minimally open retractiondevice or retractor may be formed as an integral unit that is referencedas 800. The retractor 800 includes blades 710, 720 having respectiveproximal ends 712, 722. The blades 710, 720 include distal end portions714, 724. The distal end portions 714, 724 are connected at their ends,thus the retractor 800 is an integrated device. The distal end portions714 of the blade 710 are spaced apart from one another and define anarcuate cut-out 713. Similarly, the distal end portions 724 of the blade720 are spaced apart from one another and define an arcuate cut-out 723.The arcuate cut-outs 713, 723 cooperatively define an opening 832 thatextends through the retractor 800 and permits access through theretractor 800 to the operative site similar to the opening 632 ofretractor 600. A pair of feet 816 is attached to the region where thedistal end portions 714, 724 join together. The feet 816 extend outwardsfrom the opening 832 and include a hole 802. The blades 710, 720 can bemanipulated by the practitioner towards each other (FIG. 7B) such thatthe retractor 800 is in a first condition and ready to be inserted intoa minimal incision in the patient's skin. Once the retractor 800 isinstalled through the skin and into the operative site, the blades 710,720 may be spread apart (i.e. a second condition) as previouslydiscussed in detail hereinabove with respect to the retractor 600.

Referring now to FIGS. 8 and 9, in conjunction with FIG. 4E, a method ofusing the retractor 500 is disclosed. A method and supporting structuresfor using the retractor 500 are disclosed in U.S. patent applicationSer. No. 11/528,223, filed on Sep. 26, 2006, owned by the assignee ofthe present application, the entire contents of which are herebyincorporated by reference. An example of a temporary set screw 16 a isillustrated in FIG. 8. The temporary set screw 16 a includes threads 18a at a distal end thereof. The threads 18 a are adapted to engagecorresponding thread structures in the head 12 of the pedicle screw 10(FIG. 1C). At the opposing end of the temporary set screw 16 a is a headthat is adapted to engage driving tools as are known in the art.

Initially, the practitioner installs a pair of pedicle screws 10 usingknown open or mini-open surgical techniques and instruments.Alternatively, percutaneous placement of the pedicle screws 10 iscontemplated by any suitable technique. In this regard, the methods anddevices of the aforementioned U.S. patent application Ser. No.11/528,223 may be particularly useful if the pedicle screws 10 areinstalled percutaneously in the selected locations, with an incisionmade through the patient's skin such that the incision spans thedistance between the pedicle screws. The practitioner then dissects aminimum amount of tissue between the pedicle screws 10 and installs anarcuate member 430 therebetween. The arcuate member 430 includes rodportions 440, 450 that are received in the channels 14 of the pediclescrews 10. Subsequently, a pair of temporary set screws 16 a isinstalled into the heads 12 of the pedicle screws 10 and secure thearcuate member 430 in its desired position. By securing the arcuatemember 430 to the pedicle screws 10, the relative position of thepedicle screws 10 to each other is maintained throughout the surgicalprocedure.

Alternatively, the practitioner may substitute a different retractor forretractor 500. For example, the retractor 700 is installed by insertingone of the blades 710, 720 into the incision such that the shafts of thetemporary set screws 16 a pass through the holes 702. Once the firstblade is installed, the remaining blade is installed in the same manner.With the blades 710, 720 installed in the operative site, thepractitioner spreads the blades 710, 720 apart from one another andretracts tissue surrounding the operative site. The practitioner maygrasp the blades 710, 720 and retract the tissue or may use aconventional retractor, such as a Gelpi retractor 850, to move theblades 710, 720. Alternately, the practitioner may select the retractor800 for the procedure. In this instance, the practitioner inserts theretractor 800 into the incision and positions the retractor 800 suchthat the holes 802 are aligned with the temporary set screws 16 a.Moving the retractor 800 towards the pedicle screws 10 couples theretractor 800 to the pedicle screws 10 by inserting the shafts of thetemporary set screws 16 a through the holes 802 of the retractor 800.The practitioner then manually separates the blades 810, 820 of theretractor 800 and retracts tissue surrounding the operative site. Afterthe tissue is retracted, the practitioner may perform procedures on theaccessible region such as a diskectomy, rod stabilization, prostheticinstallation, etc.

Additionally, the minimally invasive retraction structures disclosed inU.S. patent application Ser. No. 11/528,223 may be used in conjunctionwith either retractor 700 or retractor 800. In this configuration,incisions and openings are created in the patient's skin using knowntechniques. The pedicle screws 10 are then installed in their desiredlocations. The pedicle screws 10 may be installed prior to installingthe minimally invasive retractors 60 or they may be installed as anassembled unit. Once the minimally invasive retractors 60 are installedover the pedicle screws 10, the practitioner either manually separatesthe blades to retract tissue surrounding the pedicle screw 10 or employsa conventional retractor (e.g. a Gelpi retractor) to separate the bladesand retract tissue around the pedicle screw 10. Once the tissue aroundthe pedicle screws 10 is retracted, the practitioner then makes anincision between the pedicle screws 10 and dissects a minimally openregion for inserting the arcuate member 830. Once the arcuate member ispositioned, the practitioner performs the steps previously discussed.

Each of the presently disclosed embodiments provides a retractor thatcan be inserted through a minimal opening. In addition, the retractorsare reconfigurable after installation such that the practitioners canretract tissue surrounding the operative site. The presently disclosedembodiments of the retractor also include orifices on the blades thatare configured for cooperating with a convention retraction instrumentsuch as a Gelpi retractor. Further still, the retractors provide anaccess opening for inserting or removing various instruments,prosthetics, or tissue. In conjunction with the above, pedicle screwsmay be installed and act as anchors points for the retractors andfurther increasing the options available to the practitioner duringsurgical procedures.

In each of the disclosed embodiments, a funnel-shaped access opening isdefined which is wider at the proximal, skin level of the incision andnarrower at the bottom, or lower section of the incision where theretractor is fixed in position relative to the pedicle screws. Contraryto prior devices which attempt to create an access opening of thereverse shape, i.e., a narrower opening at the skin level and a widenedsection below the skin adjacent the working area on the facets andinterbody space, the access opening of the present devices providesimproved visibility of the operative site and the widened top sectionallows insertion and removal of instruments and accessories (e.g.,light, suction, irrigation) without interfering with surgicalinstruments already inserted into the opening and which the surgeondesires to leave in place despite also desiring to introduce otheraccessories as mentioned above. The fixation of the lower portion of theretractor structure to the set screw is important, as the narrower endof the funnel-shaped retractor is maintained in the desired positionrelative to the anatomy to be operated upon.

It will be understood that various modifications may be made to theembodiments of the presently disclosed minimally open retraction devicesor retractors. Therefore, the above description should not be construedas limiting, but merely as exemplifications of embodiments. Thoseskilled in the art will envision other modifications within the scopeand spirit of the present disclosure.

What is claimed is:
 1. A surgical retractor comprising: a first bladehaving a first ring segment disposed at a distal end thereof, the firstring segment having first and second rod portions extending from opposeddistal ends thereof, each of the first and second rod portions defininga semi-cylindrical configuration comprising a first arcuate surface anda first mating surface opposite the first arcuate surface; and a secondblade having a second ring segment disposed at a distal end thereof, thesecond ring segment having third and fourth rod portions extending fromopposed distal ends thereof, each of the third and fourth rod portionsdefining a semi-cylindrical configuration comprising a second arcuatesurface and a second mating surface opposite the second arcuate surface,wherein alignment of the first and third rod portions comprises matingthe first and second mating surfaces of the first and third rod portionssuch that the first and second arcuate surfaces together define a firstcylindrical shape, alignment of the second and fourth rod portionscomprises mating the first and second mating surfaces of the second andfourth rod potions to define a second cylindrical shape, andapproximation of the first and second ring segments define an arcuatering at a distal end of the surgical retractor.
 2. The surgicalretractor of claim 1, wherein each of the first and second matingsurfaces includes a planar surface.
 3. The surgical retractor of claim2, wherein the planar surfaces of the first and fourth rod portionsinclude a channel.
 4. The surgical retractor of claim 3, wherein theplanar surfaces of the second and third rod portions include a rib. 5.The surgical retractor of claim 4, wherein the ribs are complementary tothe channels thereby aligning the first and third rod portions and thesecond and fourth rod portions.
 6. The surgical retractor of claim 1,wherein the mating surfaces of the first and fourth rod portions areoriented in a first direction and the mating surfaces of the second andthird rod portions are oriented in a second direction opposite from thefirst direction.
 7. The surgical retractor of claim 1, wherein thealigned first and third rod portions define a first rod end and thealigned second and fourth rod portions define a second rod end, thefirst and second rod ends insertable into respective first and secondbone screws.
 8. The surgical retractor of claim 7, further including setscrews for securing the first and second rod ends in the respectivefirst and second bone screws.
 9. The surgical retractor of claim 8,wherein the first and second blades are bendable towards and away fromeach other such that bending one of the first and second blades awayfrom the other of the first and second blades retracts tissue adjacentthe surgical retractor with the first and second bone screws acting asanchors.
 10. The surgical retractor of claim 7, wherein the first andsecond rod portions are slidable relative to the third and fourth rodportions thereby reconfiguring an opening of the arcuate ring.